POS0029 CHARACTERISING THE CLINICAL AND RADIOLOGICAL PHENOTYPE OF PSORIATIC ARTHRITIS: A CLASS I AND II HLA ALLELES STUDY
Authors: E. Espartal, A. Erra, X. Michelena, M. Almirall Bernabé, M. Lopez Lasanta, H. Borrell Paños, A. Pluma Sanjurjo, S. Sandoval, H. Avalos Bogado, S. Marsal
Journal: Annals of the Rheumatic Diseases (2022)

Background Psoriatic arthritis (PsA) is a heterogeneous disease affecting multiple tissues including skin and joints. Few studies have fully explored the association between class I and II HLA alleles and different clinical and radiological manifestations. Objectives To examine the association between different class I and II HLA alleles and certain PsA phenotypes. Methods Cross-sectional study including patients with PsA over 18 years. All patients fulfilled the CASPAR classification criteria for PsA. Demographic, clinical, laboratory and radiology data were gathered including variables related to joint phenotype, type of skin involvement and response to biological disease-modifying drugs (bDMARDs) treatment. HLA class I (A, B, C) and II (DR, DQ, DP) determinations were performed with high-resolution techniques. We explored possible associations with univariate logistic regression and applied the Bonferroni method to correct for multiple comparisons. bDMARDs resistant patients were defined if failure to two or more bDMARDs. Results A total of 246 patients were included. Mean age of the cohort was 59.8 years and 53% were men. Average articular disease duration was 12.4 years. A total of 39.8% patients had axial involvement and 90.7% peripheral, being the polyarticular the most frequent subtype in 48% of cases. Considering the skin, mean disease duration was 22.2 years, being the plaque psoriasis the most frequent subtype in 75.2% of cases. 44.3% of the patients presented a history of dactylitis whilst 24% presented enthesitis. Uveitis was reported in 3.7% of patients and Crohn’s disease in 0.4%. 30.9% of PsA patients had erosions in hand or feet x-ray. More than half (59.3%) were treated with bDMARDs with a median exposure of 2 different drugs. Table 1 shows the HLA I and II alleles with a frequency greater than 5%. Table 1. HLA class I and II alleles with frequencies greater than 5% GEN ALLELE N FREQUENCY (%) HLA-A 02:01 79 23.87 01:01 51 15.41 29:02 29 8.76 03:01 26 7.85 HLA-B 27:05 31 9.06 44:03 26 7.6 51:01 22 6.43 08:01 21 6.14 HLA-C 07:01 39 11.78 06:02 38 11.48 04:01 34 10.27 12:03 32 9.67 HLA-DR 07:01 60 18.13 01:01 37 11.18 03:01 28 8.46 HLA-DQ 05:01 60 19.8 02:02 49 16.17 03:01 39 12.87 02:01 29 9.57 HLA-B*27:05 (OR 2.3, CI 95% 1.01-5.47) and HLA-C*02:02 (OR 2.8, CI 95%, 1.08-7.55) were associated with axial involvement. HLA-DRB*03:01 (OR 3.1, CI 95%, 1.22-8.36) and HLA-DQ*02:01 (OR 3.24, CI 95%, 1.3-8.82) were associated with the polyarticular subtype, HLA-B*08:01 (OR 5, CI 95%, 1.81-14.33), HLA-C*07:01 (OR 2.65, CI 95%, 1.19-5.76) and HLA-DQ*02:01 (OR 2.55, CI 95%, 1.03-6.11) with enthesitis; HLA-A*29:02 (OR 2.68, CI 95%, 1.12-6.75) and HLA-A*11:01 (OR 2.77, CI 95%, 1.06-7.78) with dactylitis; HLA-C*06:02 (OR 2.33, CI 95%, 1.09-5.06) with nail psoriasis; HLA-C*04:01 (OR 3.52, CI 95%, 1.18-9.64) with palmo-plantar psoriasis; HLA-C*06:02 (OR 4.5, CI 95%, 1.33-23.7) and HLA-C*12:03 (OR 3.59, CI 95%, 1.05-19.05) with plaque psoriasis and HLA-A*24:02 (OR 3.03, CI 95%, 1.17-7.92) with erosions. No association was found between alleles and bDMARD resistant PsA patients. Conclusion In our cohort, we have confirmed previously described associations in the literature 1 and found new significant associations with clinical and radiographic PsA manifestations including class II HLA analysis. References [1]Haroon M, Winchester R, Giles JT, et al. Certain class I HLA alleles and haplotypes implicated in susceptibility play a role in determining specific features of the psoriatic arthritis phenotype. Ann Rheum Dis 2016;75:155–162. Disclosure of Interests None declared